Inclusion Criteria: patient age between 40 and 80, visual acuity score of 20/40 or better; spherical refraction within ± 5 diopters, cylinder refraction within ± 3 diopters, ability to cooperate with study procedures and personnel and to perform tests reliably. Case-control assignment for the human clinical trials is based on medical and ocular history and on a comprehensive eye examination (including intraocular pressure history, standard disc photography and Humphrey-Zeiss 24-2 visual field test) by a glaucoma specialist.